We all know as SQL professionals that the NULL marker is a special case. Oftentimes, you have NULL‘s stored in your tables, and that’s fine. Suppose you want to present an alternative value in query results where some of the columns have NULL? This is a perfect opportunity (but not the only) to use the IFNULL() function. I find IFNULL() quite useful when exporting query results to a CSV file or other type of flat file, providing something more meaningful than the NULL word itself. However, you only have one substitute for the NULL value when using IFNULL(), so keep that in mind. Continue reading and see examples using IFNULL() in SELECT queries…

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Sometimes, you just half to chuckle. A couple folks felt that I didn’t give enough information in my post showing how to configure a small Node.js application that could access a MySQL database. Specifically, they wanted me to explain the following:

1. Configure your Express.js and MySQL development in a single Node.js application.
2. How to convert the list of RowDataPacket objects as elements of data, which is really just simple JavaScript knowledge.
3. How to bind variables into the query.

Like the other blog post, this one assumes you’ve performed a global install of Node.js on a Linux server. If you’re unfamiliar with how to perform a global Node.js installation, I cover how to do it in this …

In my previous Blog i have explained how we can integrate MySQL tools ( Percona Tool kit ) with systemd service, At Mydbops works with multiple clients ,we get various requirements from customers a few may be a complex ones ,one of the requirement was to setup a binlog server and copy the Production binlogs instantly .

To satisfy customer request i have made a simple shell script and integrated in systemd service which does a similar job as of Maxscale Binlog Server ( Pervious blog )

In this blog i will explain how to setup a simple binlog server.

Pre-requites for setting up the Binlog server.

• A standalone remote server with required disk.
• The mysqlclient to be …

I got this question on the “How to Avoid Pitfalls in Schema Upgrade with Percona XtraDB Cluster (PXC)” webinar and wanted to answer it in a separate post.

Will RSU have an effect on GTID consistency if replication PXC cluster to another cluster?

Answer for this: yes and no.

Galera assigns its own GTID for the operations, replicated to all nodes of the cluster. Such operations include DML (

INSERT/UPDATE/DELETE

 ) on InnoDB tables and DDL commands, executed with default TOI method. You can find more details on how GTIDs work in the Percona XtraDB Cluster in this blog post.

However, DDL commands, executed with RSU method, are …

I would say that innodb_rollback_on_timeout is a very important parameter. In this blog, I am going to explain “innodb_rollback_on_timeout” and how it affects the transaction behavior at the MySQL level. I describe two scenarios with practical tests, as it would be helpful to understand this parameter better.

What is innodb_rollback_on_timeout?

The parameter Innodb_rollback_on_timeout will control the behavior of the transaction when a failure occurs with timeout.

• If –innodb-rollback-on-timeout=OFF ( default ) is specified, InnoDB rollbacks only the last statement on a transaction timeout.
• If –innodb-rollback-on-timeout=ON is specified, a transaction timeout causes InnoDB to abort and roll back the entire transaction.

Let’s conduct the test with the …

A new release of MySQL was out on July 13 (8.0.21).
Among all the changes, there are some that I have already tested and that I really appreciate.

Who stopped the MySQL server?

In previous releases, I can already see in the error log file who stopped the MySQL server if this was done through the shutdown statement.
In MySQL 8.0.20:

mysql> shutdown;
Query OK, 0 rows affected (0.00 sec)
mysql> exit;
Bye
# tail -2 /u01/app/mysql/admin/mysqld2/log/mysqld2.err
2020-07-23T20:39:08.049064+02:00 9 [System] [MY-013172] [Server] Received SHUTDOWN from user root. Shutting down mysqld (Version: 8.0.20).
2020-07-23T20:39:09.796726+02:00 0 [System] [MY-010910] [Server] /u01/app/mysql/product/mysql-8.0.20/bin/mysqld: Shutdown complete (mysqld 8.0.20)  MySQL Community Server - GPL.

In MySQL 8.0.21:

mysql> …

A new release of MySQL was out on July 13 (8.0.21).
Among all the changes, there are some that I have already tested and that I really appreciate.

Who stopped the MySQL server?

In previous releases, I can already see in the error log file who stopped the MySQL server if this was done through the shutdown statement.
In MySQL 8.0.20:

mysql> shutdown;
Query OK, 0 rows affected (0.00 sec)
mysql> exit;
Bye
# tail -2 /u01/app/mysql/admin/mysqld2/log/mysqld2.err
2020-07-23T20:39:08.049064+02:00 9 [System] [MY-013172] [Server] Received SHUTDOWN from user root. Shutting down mysqld (Version: 8.0.20).
2020-07-23T20:39:09.796726+02:00 0 [System] [MY-010910] [Server] /u01/app/mysql/product/mysql-8.0.20/bin/mysqld: Shutdown complete (mysqld 8.0.20)  MySQL Community Server - GPL.

In MySQL 8.0.21:

mysql> …

This morning, a user asked in the MySQL Community Slack if somebody had an idea why the error log was filled up continuously with a warning messages like this one:

2020-07-24T06:54:00.877128Z 46 [Warning] [MY-013360] [Server] 
Plugin sha256_password reported: ''sha256_password' is deprecated and will be removed in 
a future release. Please use caching_sha2_password instead'

The context was that the user upgraded from MySQL 5.7 to MySQL 8.0 and changed the authentication plugin of all users to caching_sha2_password.

As the warning message was written to the error log almost twice per second, I suspected a monitoring tool. The user said, that no application, no monitoring was using this server yet.

Of course we verified that all users had the plugin changed.

This is important when helping people (friends, colleagues, …

Group Replication enables you to create fault-tolerant systems with redundancy by replicating the system state to a set of servers. Even if some of the servers subsequently fail, as long it is not all or a majority, the system is still available.…

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There may come a time you need to rename one or more columns in an existing MySQL table for a variety of reasons. Using ALTER TABLE, to rename a column is an easy enough command. But, suppose there are multiple tables in the same database/schema that have the same-named column and all of those columns need to be renamed. That could be a lot of ALTER TABLE statements to type out. Save your energy and time, avoiding all of those ALTER TABLE commands all-together. If you are lucky enough to be working with a MySQL version > 8.0 then the Shell is your salvation. With just a few lines of Python code in \py mode, all of your trouble(s) and headache(s) are no more…

Photo by Ibrahim Rifath on …